Impact type concrete breaking machine



July 29, 1958 w. v. CORNETT- IMPACT TYPE CONCRETE'BREAKING MACHINE Original Filed July 13, 1949 4 Sheets-Sheet 1 INVENTOR. Mum k 602N577" ATTQRNEY5 July 29, 1958 W. V. CORNETT IMPACT TYPE CONCRETE BREAKING MACHINE Original Filed July 13, 1949 4 Shgets-Sheet 2 Q0 II.

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INVENTOR.

M41752 I f 622N212" w. v. CORNETT 2,845,2 58 IMPACT TYPE CONCRETE BREAKING MACHINE July 29, 1958 4 Sheets-Sheet 3 Original Filed July 13, 1949 BY KM;

July 29, 1958 w. v. CORNETT IMPACT TYPE CONCRETE BREAKING MACHINE Original Filed July 13, 1949 4 Sheets-Sheet 4 I INVENTOR. M11272}? V C'mvsrr BY Il 194m A.

A 7' TORNF Y:

IMPACT TYPE CONCRETE BREAKING MACHINE Walter V. Cornett, Los Angeles, Calif.

Continuation of abandoned application Serial No. 104,569, July 13, 1949. This application March 31, 1955, Serial No. 498,381

1 Claim. 01. 262- 15) The present invention pertains to improvements in concrete breaking machinery, the instant application being a continuation of application Serial No. 104,569, filed July 13, 1949, now abandoned.

improved chassis, wheel arrangements and steeringimeans;

Further advantages and improvements will become evident during the course of the following description in connection with the accompanying drawings, in which:

Figure lis a side elevation of a preferred form of the device;

Figure 2 is a plan iew of the same;

Figure 3'is a rear elevation of the device; v

Figure 4' is a detail rear elevation of the air-hammer sub-assembly;

Figure 5 is a vertical sectional view of the same in the plane"55, Figure '4; 9

Figure 6 is a detail view of the alternative hand or foot control for the air-motor;

Figure 7 is. a detail viewof the locking means for the latch-release lever; and

Fig. 8 is an enlarged view of the bracket 47 and the swivel 48 taken from a point between the tow bar and the, bracket, looking at the right side of Fig. 1.

Referring to Figures 1 and 2, the numeral 20 denotes a frame on which is secured a platform 21. A structural steel, axle 23 is mounted on a longitudinal central pivot 24 in. a bracket 25 secured under the front endof the frame. 20. A pair of wheels26 and 27, equipped with pneumatic tires 28' and 29, are mounted on spindle,

members 30 and 31 which in turn are pivoted on kingpins 32 and 33in the ends of theaxle 23. Rearwardly extending arms 34 and 35 on the members 30 and 31 are linked by a transverse tie-rod 36. A knuckle lever member 37, formed on or secured to the arm'35, is

connected by a rod 38 with the downwardly extending arm 39 of a steering gear 40. The gear 40 is operable in the usual manner by a suitable steering wheel 41 mounted on arearwardly inclined post 42.

A pair of angular radius rods 43 are horizontally United Sttes Patent 0 bracket 47 carries a horizontally pivoted towbar.49 which when. not in use may be held in upwardly retracted position bya chain 50 as shown in Fig. 1. A rearward extension 51 of the bracket 47 is, linked by a rod 52 with the spindle lever 34, Figure 2.

From the foregoing description it will be evident that the device maybe steered by the wheel 41 and related mechanism after the manner of an automobile or truck. When the machine is being towed, the provision of the link rod 52 causes the wheels 26, 27 to be steered in response to the lateral swings of the bracket 47,, thus causing the device to follow readily the changesincourse. of the towing vehicle. The steering gear 40 is of a type sufficiently reversible to prevent interference with the latterly described steering action when towing is done without. a rider on the machine to manipulate the steering wheel 41. v

A pair of rear wheels 53 and 54, also equipped with pneumatic tires 55 and 56, are mounted on spindles 5,7. and 58. fixed in legs 59 and 60 extending downward from the rear corners of the frame 20, Figure 3.

Brake shoes 61 and 62, adapted to engage the rear tires; 55 and 56, are mounted on a transverse rocker. shaft 63. 'A brake lever 64, having its handle .65; disposed, below the steering wheel 41,, is adapted to operate thev shaft 63 through linkage similar to that shown in the previously mentioned application Serial No. 33,603 and therefore not requiring detail description herein. A reversible air motor 66 is horizontally pivoted at 67 to an upwardly extending lug. 68 onfthe frame 20, Fig. 3. A drive chain 69normallyconnects the motor 66 with a large sprocket 70. secured to the left rear wheel 54. A latch pin 71, Fig. 2, engaginga plate 72 on the frame 20, is adapted'to holdthe motor 66in.

normal position on the pivot 67. A red 73, hinged" at its, lower endto the frame 20, carries a compression spring 74 engaging a small bracket 75 on the rear, portion of themotor 66, the rod being slidable through the bracket. I i

The purpose of the above described; pivotal motor mounting'is to facilitate disconnecting the chain drive when it is desired to tow the machine at speeds which' would otherwise over-speed the idling air motor. To. accomplish this purpose, the latch pin71 is. first- With-2 drawn. The major portions of the motor 66, including its driving sprocket, are disposed rearwardly of the,

pivot- 67, but when the latch pin 71 is withdrawn the spring 74 prevents the motor from toppling sharply downward. By this means possible injury to the operator is avoided. The motor is then pressed downward, allowingthe' chain 69 to be disengaged from the sprocket 7.0; and placed on retaining hooks 76' and77 on the frame 20, Figs. 2 and 3. in normal position, the hooks 76 and 77 holding the chain 69"clearof thesprocket 70 topermit free towing.

The spring 74, in addition to its above-noted safety functions, facilitates return of the motor 66 to normal position either after disengagement or during replacement of the chain, by providing a counter-balance effect against the motors weight.

Two pairs'of upright channel guides 78 and 79, of the rods 82' disposed in spring-backed guides 83' mounted on the top plates 80. Spring-pressed swing latches 84, pivotally mounted on thetop guides 83, normally engage selected notches '85 the rods 82, thereby holding the" 2 air cylinder. assembly at any desired vertical'p'osition'in the manner also set 'forth in the above-mentioned'appli- Thereafter the motor 66 maybe re-latched" 3 cation. A transverse shaft 86 having short levers 87 connected by pull rods 88 with the latches 84, is rockable via a link 89 by a transverse control lever 90 to withdraw the latches from the notches 83 when setting the cylinder height, as hereinafter described in detail.

The cross-head blocks 81 have rockably mounted therein a pair of trunnions 91 extending laterally from a lower air cylinder head 92, the latter being shown in detail in Figures 4 and 5. A cylinder 93, held between the lower head 92 and an upper head 94 by bolts 95, is provided with lower and upper air ports 96 and 97. A piston rod 98, slidably guided in the lower head 92 and provided with a spring-pressed packing gland 99, carries on its upper end a piston 100 slidable in sealing relation in the cylinder 93. A heavy hammer 101 is secured to the lower end of the piston rod 98. The hammer is adapted to interchangeably hold tools 102 of any type suitable to the work required, such as cutters, breakers, tampers, etc.

A semi-elliptic leaf spring 103, Figure 1, attached to the outer end of one trunnion 91, engages a vertical angle guide member 104 to normally hold the air-cylinder assembly vertical but to allow a small degree of resiliently controlled swing in the cross-head blocks 81 during certain types of work.

A suitable driving and operating seat 105 is secured to a rearwardly extending angular post 106 pivotally held in a coupler member 107 centrally attached to the rear of the frame 20. By means of the above pivotal mounting the seat 105 may be adjusted to various lateral positions with respect to the center line of the machine or may be lined up directly thereon, the desired position being retained by suitable clamping means such as a setscrew 108, Figures 2 and 3.

A bracket 109, secured to the rear angular brace 110 of the rear guide channel member 78, carries a main air valve 111 controllable via a pilot valve 112 by a rocking handle 113. A linkage including a push-rod 114, a rocker combination 115 and a pull-rod 116 also operatively connects the pilot valve 112 with a pedal 117 hinged to the deck 21. By this means optional hand or foot control of the pilot valve 112 and main valve 111 is provided.

The main valve 111 has an upwardly extending inlet conduit 118 and a downwardly extending exhaust pipe 119 terminating in a mufiler 120, Figure 1. Two delivery pipes 121 and 122, Figures 1 and 3, are connected by flexible hoses 123 and 124 respectively with the lower and upper ports 96 and 97 of the air cylinder 93, the hoses being cut away in Figure 2 to avoid concealing underlying parts.

The air inlet conduit 118 receives compressed air via an oil feeder 125, an auxiliary throttle valve 126 and a coupling 127 adapted to be connected by a long hose 128, Figure 3, to any suitable source of supply such as the usual portable air compressor (not shown).

The motor 66 receives its compressed air supply through a flexible hose 129, Figure 3, a pipe 130, and a control valve 131 from the main inlet conduit 118. The control valve 131 and its operating means are shown in detail in Figure 6. Referring to the latter figure, the valve 131 is of the well-known whistle type having a plunger 132 normally pressed outward by an internal spring (not shown) to hold the valve in closed position. A lever 133, pivoted at 134 to a stationary yoke 135, engages the top of the plunger 132. A pull-rod 136 connects the free end of the lever 133 with a second pedal 137 hinged to the deck 21. A stem 138, threaded through the upper arm 139 of the yoke 135, is surmounted by a hand knob 140. A compression spring 141 is disposed on the stem 138 under the knob 140.

By turning the knob 140 the end of the stem 138 may be brought into engagement with the lever 133 to depress the latter and thus open the valve 131 to any set degree. By this means manual control of the valve is 4 provided, a typical use being when the valve is set to admit air at a constant set rate to the air motor 66 in order to propel the machine at any desired fixed speed. If during a constant speed setting of the valve a temporary increase in speed is desired, the pedal 137 may be depressed to widen the valve opening for the time required, after which release of the pedal allows the original speed to be resumed automatically. It will be obvious that the stem 138 may also be set to allow full closure of the valve 132 and the latter may then be controlled entirely by the pedal 137, thus freeing the operators hand for other operations when necessary or convenient. The spring 141 serves to prevent changes in the adjustment of the stem 138 by vibration. A reversing control lever 142 is disposed on the motor 66, Figure 3.

In a typical use of the machine, for example cutting a trench in a concrete pavement, the operator controls all normal operative functions from his position on the seat 105. He actuates the valve 111 to admit compressed air alternately to the upper and lower ends of the cylinder 93, thereby causing the hammer 101 to drive the tool 102 into the material to be cut in successive blows. At the same time he controls the air motor 66 to propel the device and steers the latter along the cutting line by means of the wheel 41. A vertical rod 143, Figure 5, is secured to a rearward extension 144 of the hammer 101 and slides through a guide 145 on the lower cylinder head 92 as the hammer reciprocates, thus preventing the hammer and hence the tool 102 from turning with respect to the cutting line.

It will be evident that the grouping of all controls within easy reach of the operator and the provision of optional hand and foot control for both the hammer and the propelling motor permit the user a wide degree of flexibility in adapting his control operations to the particular type of work in progress, thus contributing to maximum speed and efficiency of performance. As an illustration, 'for ordinary cutting or breaking work the operator may readily steer the device with his left hand while actuating the hammer valve 111 manually and the controlling air motor valve 131 by means of his right foot on the pedal 117. In types of work where it is necessary to follow a cutting line with great accuracy, as for example in curb-stone trenching and the like, the operator may control the hammer action by his left foot on the pedal 137 and the propulsion by his right foot, thus making both hands available for precision steering. In either of the above cases, if desired, a fixed normal speed of propulsion may be provided by initially setting the valve 131 by means of the knob 140.

In the previously mentioned application Serial No. 33,603 is set forth a method of raising the operating position of the air cylinder by resting the hammer against a supporting surface, releasing vertical retaining latches, and admitting compressed air to the upper end of the cylinder. Obviously the operation may be carried out in the same manner with the device described herein, but the present embodiment includes means by which pneumatic elevation of the cylinder 93 may be accomplished independently of the nature or availability of a suitable surface under the hammer, and also means to prevent too violent elevation of the cylinder by careless admission of full air pressure with consequent danger of injury to the machine and operator.

Referring to Figure 5, it will be seen that the lower side of the hammer extension 144 comprises a hook 144a. The numeral 146, Figures 2 and 3, designates a heavy chain attached to both ends to the channel guides 78 and 79. During normal operation of the device the chain 146 is looped up over a retaining cleat 147 so as to clear the hammer extension 144. Assuming the device to have been working with the air cylinder in low position, when it is desired to raise the assembly the hammer 101 is first brought to its top relative position and the chain 146 is slung down so as to loop under the extension 144 as shown in Figure 2. Thereafter, when the latches 84 are released by the lever 90 and compressed air is admitted to the top of the cylinder 93, the chain 146 prevents the hammer 101 and consequently the piston 100 from moving downward, with the result that the cylinder assembly is moved upward until it is relatched in the desired elevated position.

It is believed evident that the above described arrangement is advantageous in confining the lifting stresses to the structure of the machine itself, removing any danger of tipping or shifting the machine by pressure against an outside surface, and also in permitting pneumatic elevation in cases where no external backing surface is available for the hammer, as for example when the device has been working over and in a deep trench or hole at the lowest level in its range. The chain 146 may also be used to support the hammer while the machine is being towed.

When the cylinder assembly is being elevated pneumatically it is important to prevent a sudden rush of high pressure air from driving the cylinder upward with destructive violence, as previously noted. This is accomplished by means of the auxiliary throttle valve 126. Prior to unlatching the cylinder assembly, the valve 126 is partially closed so as to allow only a slow passage of air to the main control valve 111. The latches 84 are then released and the main control valve 111 opened wide, whereupon the throttled air flow raises the cylinder assembly with comparative slowness, allowing easy determination of the desired position and re-latching therein.

It is a wellknown characteristic of the public, particularly children, to move any prominent lever on an unattended machine. When a device of the type described herein is left unattended no air pressure is normally connected thereto, so that tampering with the various air control devices under such circumstances is not dangerous. However, inadvertent release of the latches 84 could cause damage by allowing the air cylinder assembly to drop violently. To guard against such inadvertent release either by an unauthorized person or by the operator himself, a retaining hook 148 is pivoted to the rear channel guide 79 at 149 as shown in Figure 7. This book rests by gravity on and around the rear of the transverse lever 90, thus preventing the latter from being moved rearwardly to release the latches 84 unless the hook 148 is intentionally lifted for the purpose.

Referring to Figure 3, it will be seen that the vertical center-line of the air cylinder mechanism, that is the line of action of the hammer 101, is located well within the polygon determined by the points of contact of four tires with the supporting surface, being disposed substantially at the geometric center of the frame 20, the weight of the machine and an average operator being also approximately centered in this location.

This balanced construction, with the line of impact substantially centered within the frame 20, provides the operational advantages of steadiness and absence of surging and rocking, high capacity in small space, utilization of the pneumatic tires for cushioning, and the related qualities which have been fully set forth in the above mentioned application Serial No. 33,603 and which consequently need not be set forth in detail herein. However, the present embodiment provides the additional advantages of four wheel construction with improved steering qualities, ability to straddle ditches, and the like, while at the same time the provision of the rocking pivot 24 preserves the principle of three-point support of the operating apparatus, with this principles inherent quality of balance and stability on irregular surfaces.

While the invention has been described in preferred form it is not limited to the exact structures illustrated, as obviously various modifications and changes may be made without departing from the scope of the appended claim.

What is claimed is:

A concrete breaking machine comprising a frame, a pair of spaced front wheels supporting the forward end of said frame, a pair of spaced rear wheels supporting the rearward end of said frame, driving means for one of said rear wheels, control means at the rear of said frame for controlling said driving means, a vertically reciprocable hammer assembly mounted on the longitudinal center line of the vehicle adjacent the rear end thereof but forwardly of said rear wheels, means for steering said front Wheels including a generally longitudinally extending steering shaft disposed in laterally offset relationship to the longitudinal center line of the vehicle to clear and pass by said hammer assembly and terminating at the rear of said frame in a steering wheel, control means for actuating said hammer assembly including mechanism terminating in a handle offset laterally from the longitudinal center line of the vehicle on the opposite side from said steering wheel, and an operators seat disposed and mounted on the rear of said frame substantially on the longitudinal center line of the vehicle whereby an operator may manipulate said steering wheel and said control handle for the hammer assembly with opposite hands.

References Cited in the file of this patent UNITED STATES PATENTS 693,939 Yeakley Feb. 25, 1902 1,037,875 Craig Sept. 10, 1912 1,164,925 Clapp Dec. 21, 1915 1,541,392 Reaney June 9, 1925 1,543,958 Sutherland June 30, 1925 1,891,222 Cornett Dec. 20, 1932 1,915,816 Cole June 27, 1933 2,107,384 McQueen Feb. 8, 1938 2,171,255 Keeler Aug. 29, 1939 2,218,510 Albertson et a1. Oct. 22, 1940 2,293,396 Mathews Aug. 18, 1942 2,335,172 Cornett Nov. 23, 1943 2,348,445 Bayer May 9, 1944 2,423,787 Mosena et a1. July 8, 1947 2,592,194 Schmalzried Apr. 8, 1952 FOREIGN PATENTS 14,081 Netherlands Jan. 15, 1926 

